Air control element for an agricultural vehicle

ABSTRACT

The invention relates to an air control element for an agricultural vehicle which has an internal combustion engine and an exhaust after-treatment device to discharge and clean the exhaust stream. The air control element cools a component of the exhaust after-treatment device.

TECHNICAL FIELD

The present disclosure relates to an air control element which cools acomponent of an exhaust after-treatment device which discharges andafter-treats the exhaust stream of an internal combustion engine.

BACKGROUND

The current legislation regarding adherence to pollutant limits inagricultural machines, which currently manifests itself in the USA as“final tier 4” and in Europe as “Stage IV,” has resulted in higherexhaust temperatures. This became necessary, since the components of theexhaust after-treatment device, which can be an oxidation catalyticconverter, a particle filter, or an SCR catalytic converter, can onlybecome effective under the condition of an increased exhausttemperature. Higher exhaust temperatures, however, simultaneously resultin higher temperatures of the individual components of the exhaustafter-treatment device and their surfaces. This requires protectionagainst the increased heat radiation in areas in the immediate vicinityof components of the exhaust after-treatment device. Sensors and cablesin particular are to be protected against increased heat input. Inaddition, however, excessively heated surfaces are to be protectedagainst unintended access by operating personnel, in order to preventinjury in the form of burns.

Known solutions for the above-described problem use one or more Venturinozzles in the course of the exhaust pipe or exhaust air which isproduced by the fan of the engine cooling system. While the use ofVenturi nozzles is done at the cost of the exhaust pressure, the use ofcooling exhaust results in an additional parasitic load for the fan,since the exhaust air must be channeled in the direction of the exhaustafter-treatment device and cannot be discharged into the environmentwith as little resistance as possible.

The object of this invention therefore consists of at least partiallyeliminating the described deficiencies.

SUMMARY

According to an aspect of the present disclosure, an air control elementcools a component of an exhaust after-treatment device which dischargesand after-treats the exhaust stream of an internal combustion engine.The air control element forms a multi-pass air control channel oppositethe component.

The air control element produces a cool air flow stack effect. Theprocess uses a freely available energy source produced by thetemperature difference between the surface of the components of theexhaust after-treatment device and the ambient air. In addition to thedirect insulation of the components of the exhaust after-treatmentdevice by the air control element, the surface of the air controlelement is further cooled by active cooling. Finally, however, thecomponents of the exhaust after-treatment device are not cooled, or nottoo strongly cooled, such that the exhaust after-treatment process couldbe negatively affected. In the context of this application, “multi-pass”is understood to be an arrangement which encompasses two air controlchannels or correspondingly two sections for air control, wherein theflow direction of the cool air can run in both channels or sections,both in the same direction as well as in opposite directions. In thecase of opposite directions, the flow direction in one channel orsection is opposite the exhaust flow direction and the flow direction inthe other channel or section is in the direction of the exhaust flowdirection.

Preferably the air control element is arranged parallel to a directionof exhaust flow. This arrangement guarantees that the air controlelement and the components of the exhaust after-treatment device areadjacent to each other across a section as large as possible.

The air control element preferably includes a fresh air intake openingnear a downstream end of the air control element positioned downstreamin relation to the direction of exhaust flow. This guarantees that freshair is suctioned, for example, into an elevated area for an exhaust flowdirection aimed vertically upward.

It is preferred that the air control element includes an outlet openingnear a downstream end of the air control element in relation to thedirection of exhaust flow. This guarantees that the cool air leaves theair control element after it has been indirectly heated to the maximumextent by the exhaust flow.

The air control element preferably includes two air channel sectionsrunning parallel next to each other, wherein a second air channelsection is positioned inside a first air channel section. As a resultthere is a good thermal insulation of the component of the exhaustafter-treatment device with a simultaneous cooling of the surroundingair control element.

The two control channel sections have interior open ends which areadjacent to each other so that air flows out of one channel and into theother. Preferably, these interior open ends are near a lower end of theair control element. The two control channel sections can be positionedparallel to each other.

The interior open ends are preferably positioned near an upstream end ofthe component. Because the intake opening and the outlet opening arepositioned downstream and the interior open ends are positioned on theopposite upstream end, a maximum total length of both control channelsections can be achieved.

Preferably the air control element circumferentially surrounds thecomponent of the exhaust after-treatment device. This guarantees aneffective encapsulation of the component of the exhaust after-treatmentdevice by the air control element.

The component of the exhaust after-treatment device preferably includesan SCR catalytic converter. This guarantees that the SCR catalyticconverter is effectively encapsulated as a part of the exhaustafter-treatment device, in order, on one hand, to avoid an unintentionaltouching by operating personnel and, on the other hand, to maintain atemperature level in the SCR catalytic converter, so that properfunctioning is ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an agricultural vehicle with an exhaustafter-treatment device embodying the invention; and

FIG. 2 is a sectional view along the cut line 2-2 in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

At least one example embodiment of the subject matter of this disclosureis understood by referring to FIGS. 1 and 2 of the drawings.

Referring to FIG. 1, an agricultural work vehicle 10, such as a tractorwith an operator platform or cabin 16, has a frame 14 and an internalcombustion engine 12 with an exhaust after-treatment device 20 todischarge and clean the exhaust. The engine 12 is positioned as usualinside an engine compartment 18. The operator platform 16 canalternatively be designed as an open operator platform. Furthermore,parts of the exhaust after-treatment device 20 can be positioned insidethe engine compartment 18, for example an oxidation catalytic converteror a particle filter.

The exhaust after-treatment device 20 includes an exhaust pipe element24 which exits downward from the right side of the engine compartment18. The exhaust pipe element 24 is surrounded for protection by asheathing tube 26. The sheathing tube 26 can be in sections. A lowerpart of the exhaust pipe element 24 is secured to the frame 14 or to anengine-transmission unit which encompasses the internal combustionengine 12 via a holding traverse 28. The holding traverse 28 isconnected with the exhaust pipe element 24 via suitable fastening means,for example clips. In the further course of the system, the exhaustafter-treatment device 20 or the exhaust pipe element 24 forms aU-shaped bend, in order to extend primarily vertically along a cornerpost of the cabin 16 and then to discharge to the environment via adischarge opening 30. The exhaust flows in a vertically upwardlydirection R.

The vertically upward running part of the exhaust after-treatment device20 forms a first lower section 32 with a tank-shaped construction and asecond upper section 34 with a pipe-shaped construction. The lowersection 32 has a tank-shaped construction in order to be able to hold acomponent 22 of the exhaust after-treatment device 20, for example inthe form of an SCR catalytic converter 36.

Referring now to FIG. 2, the SCR catalytic converter 36 has acylindrical construction. The SCR catalytic converter 36 iscircumferentially surrounded by an air control element 40 fitted to itsshape, wherein the air control element 40 preferably is positionedconcentric to the SCR catalytic converter 36. The air control element 40includes a first or outer cylindrical element 42 and a second or innercylindrical element 44. The second cylindrical element 44 is preferablypositioned concentrically inside the first cylindrical element 42 andthe second cylindrical element 44 surrounds, preferably concentrically,the SCR catalytic converter 36. As a result of this arrangement, the aircontrol element 40 forms a multi-pass air control channel 46 whichsurrounds the SCR catalytic converter 36. A first air control channel 48is thereby formed between the first and the second cylindrical element42, 44 and a second air control channel 50 is formed between the secondcylindrical element 44 and the SCR catalytic converter 36.

The first air control channel 48 includes an intake opening 56 for freshair positioned near a downstream end area 52 of the air control element40 in relation to the exhaust flow direction. The intake opening 56 isdesigned as a louver constructed along the circumference of the firstcylindrical element 42. Ambient air or cool air is supplied via theintake opening 56 to the first channel 48. The ends of two controlchannels 48, 50 near the upstream end of the component 22 are open toeach other and to an overflow chamber 58. Air flows though channel 48,overflow chamber 58 and into channel 50. The second control channel 50includes an outlet opening 60 positioned near a downstream end 52 of theair control element 40 in relation to the exhaust flow direction. Thecool air from the air control element 40 flows through the outletopening 60 and through an intermediate area 62 between the exhaust pipeelement 24 and the sheathing tube 26.

The air control element 40 interacts with and cools the encased SCRcatalytic converter 36. As a result of the surface of the SCR catalyticconverter being heated by the operation of the internal combustionengine 12, the air located in the second control channel section 50 isheated and rises in the direction of the outlet opening 60. Because ofthe resulting suction effect, cool air is drawn in through the intakeopening 52 the first air channel 48 and the overflow chamber 58. Thisair circulation cools the SCR catalytic converter 36.

LIST OF REFERENCE CHARACTERS

-   10 Work vehicle-   12 Internal combustion engine-   14 Frame-   16 Operator platform-   18 Engine compartment-   20 Exhaust after-treatment device-   22 Component-   24 Exhaust pipe element-   26 Sheathing tube-   28 Holding traverse-   30 Discharge opening-   32 Lower section-   34 Upper section-   38 SCR catalytic converter-   40 Air control element-   42 Cylindrical element-   44 Cylindrical element-   46 Air control channel-   48 Control channel section-   50 Control channel section-   52 End area-   54 End area-   56 Intake opening-   58 Overflow chamber-   60 Outlet opening

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such illustration and description isto be considered as exemplary and not restrictive in character, it beingunderstood that illustrative embodiments have been shown and describedand that all changes and modifications that come within the spirit ofthe disclosure are desired to be protected. It will be noted thatalternative embodiments of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations that incorporate one or more ofthe features of the present disclosure and fall within the spirit andscope of the present invention as defined by the appended claims.

What is claimed is:
 1. An air control element for an agricultural workvehicle having an internal combustion engine, an exhaust after-treatmentdevice to discharge and after-treat an exhaust stream from the internalcombustion engine, a component of the exhaust after-treatment devicebeing cooled by the air control element, wherein the air control elementcomprises: a multi-pass air control channel adjacent the component. 2.The air control element of claim 1, wherein: the air control element isarranged parallel to an exhaust flow direction.
 3. The air controlelement of claim 1, wherein: the air control element includes an intakeopening for cool air near a downstream end of the component in relationto the exhaust flow direction.
 4. The air control element of claim 1,wherein: the air control element includes an outlet opening near adownstream end of the air control element in relation to the exhaustflow direction.
 5. The air control element of claim 1, wherein: the aircontrol channel includes a first control channel and a second controlchannel positioned inside the first control channel.
 6. The air controlelement of claim 5, wherein: an overflow chamber is formed near an endof the component; and the first control channel has an open end whichcommunicates with an open end of the second control channel via theoverflow chamber.
 7. The air control element of claim 6, wherein: theoverflow chamber and the open ends are positioned near an upstream endof the component.
 8. The air control element of claim 1, wherein: theair control element circumferentially surrounds the component.
 9. Theair control element of claim 1, wherein: the component comprises an SCRcatalytic converter.